Light emitting device

ABSTRACT

A light emitting device includes a substrate, a plurality of light emitting cells separated from each other and disposed on the substrate, and a plurality of conductive interconnection layers electrically connecting two neighboring light emitting cells. Each light emitting cell includes a light emitting structure including a first conductivity-type semiconductor layer, an active layer and a second conductivity-type semiconductor layer, a first electrode, a second electrode, and an etching area. The light emitting structure further includes a first side surface and a second side surface, and if a width between the first side surface and the second side surface is defined as W, the second electrode is disposed in an area between a position separated from the first side surface by 
               1   5     ⁢   W         
and a position separated from the first side surface of the light emitting structure by
 
     
       
         
           
             
               1 
               2 
             
             ⁢ 
             
               W 
               .

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. patentapplication Ser. No. 14/072,070, filed Nov. 5, 2013, which claimspriority under 35 U.S.C. §119 to Korean Patent Application No.10-2012-0126523, filed in Korea on Nov. 9, 2012, which are herebyincorporated herein by reference.

BACKGROUND

1. Field

Embodiments relate to a light emitting device.

2. Background

Light emitting devices, such as light emitting diodes or laser diodesusing group III-V or II-VI compound semiconductor materials, generatelight of various colors, such as red, green, blue, and ultravioletlight, due to development of thin film growth techniques and devicematerials, and generate white light having high efficiency usingfluorescent materials or through color mixing. Further, light emittingdevices exhibit low power consumption, semipermanent lifespan, fastresponse time, safety, and eco-friendliness, as compared to conventionallight sources, such as fluorescent lamps and incandescent lamps.

Therefore, light emitting devices are increasingly applied totransmission modules of optical communication units, light emittingdiode backlights substituting for cold cathode fluorescent lamps (CCFLs)constituting backlights of liquid crystal display (LCD) devices,lighting apparatuses using white light emitting diodes substituting forfluorescent lamps or incandescent lamps, head lights for vehicles, andtraffic lights.

In case of a horizontal type light emitting device, a light emittingstructure including an n-GaN layer, an active layer, and a p-GaN layeris generally stacked on a sapphire substrate. Due to characteristics ofthe horizontal type light emitting device, an n-electrode and ap-electrode are horizontally formed and may cause high current spreadingresistance. Such a problem occurs even in a light emitting device inwhich plural light emitting cells are connected in series or inparallel. Therefore, in order to enhance current spreading, thepositions of the n-electrode and the p-electrode need to be optimized.

The above references are incorporated by reference herein whereappropriate for appropriate teachings of additional or alternativedetails, features and/or technical background.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments will be described in detail with reference to thefollowing drawings in which like reference numerals refer to likeelements wherein:

FIG. 1 is a plan view and a circuit diagram of a light emitting devicein accordance with one embodiment;

FIG. 2 is an enlarged view of the portion A of FIG. 1;

FIG. 3 is a cross-sectional view taken along the line P-P of FIG. 2;

FIG. 4 is a graph illustrating output power (Po.) and operating voltage(Vf) according to positions of a second electrode when the secondelectrode is disposed in accordance with the embodiment;

FIG. 5 is an enlarged view of the portion B of FIG. 1;

FIG. 6 is a plan view and a circuit diagram of a light emitting devicein accordance with another embodiment;

FIG. 7 is an enlarged view of the portion C of FIG. 6;

FIG. 8 is a top view of a portion of a light emitting device inaccordance with another embodiment;

FIG. 9 is a view illustrating a light emitting device package having alight emitting device in accordance with one embodiment;

FIG. 10 is a view illustrating a display device having light emittingdevice packages in accordance with one embodiment; and

FIG. 11 is a view illustrating a lighting apparatus having lightemitting devices or light emitting device packages in accordance withone embodiment.

DETAILED DESCRIPTION

Hereinafter, embodiments will be described with reference to the annexeddrawings.

It will be understood that when an element is referred to as being ‘on’or ‘under’ another element, it can be directly on/under the element, andone or more intervening elements may also be present. Expression of ‘on’and ‘under’, may include the meaning of the downward direction as wellas the upward direction based on one element.

In the drawings, the thicknesses or sizes of respective layers areexaggerated, omitted, or schematically illustrated for convenience andclarity of description. Further, the sizes of the respective elements donot denote the actual sizes thereof.

FIG. 1A is a plan view of a light emitting device in accordance with oneembodiment, FIG. 1B is a circuit diagram of the light emitting device,FIG. 2 is an enlarged view of the portion A of FIG. 1, and FIG. 3 is across-sectional view taken along the line P-P of FIG. 2.

With reference to FIGS. 1A to 3, a light emitting device 100A inaccordance with this embodiment includes a substrate 110, a plurality oflight emitting cells 100 separated from each other and provided on thesubstrate 110, and a plurality of conductive interconnection layers 170electrically connecting two neighboring light emitting cells 100.

The substrate 110 may be formed of a material proper for semiconductormaterial growth, i.e., a material having high thermal conductivity. Forexample, the substrate 10 may be formed of at least one of sapphire(Al₂O₃), SiC, GaAs, GaN, ZnO, Si, GaP, InP, Ge, and Ga₂O₃. Impuritiesmay be removed from the surface of the substrate 110 by performing wetcleaning upon the substrate 110.

The plural light emitting cells 100 separated from each other areprovided on the substrate 110.

The light emitting cells 100 may include light emitting diodes (LEDs)using a plurality of compound semiconductor layers, for example, groupIII-V compound semiconductor layers, and the LEDs may be blue, green, orred LEDs emitting blue, green, or red light, white LEDs, or UV LEDs.Light may be emitted from the LEDs using various semiconductors, and thedisclosure is not limited thereto.

With reference to FIG. 3, each of the plurality of light emitting cells100 includes a light emitting structure 120 including a firstconductivity-type semiconductor layer 122, an active layer 124 and asecond conductivity-type semiconductor layer 126, a first electrode 130disposed on the first conductivity-type semiconductor layer 122, and asecond electrode 140 disposed on the second conductivity-typesemiconductor layer 126.

For example, the light emitting structure 120 may be formed using amethod, such as metal organic chemical vapor deposition (MOCVD),chemical vapor deposition (CVD), plasma-enhanced chemical vapordeposition (PECVD), molecular beam epitaxy (MBE), or hydride vapor phaseepitaxy (HVPE), and the disclosure is not limited thereto.

The first conductivity-type semiconductor layer 122 may be formed of asemiconductor compound, for example, a group III-V or group II-VIcompound semiconductor. Further, the first conductivity-typesemiconductor layer 122 may be doped with a first conductivity-typedopant. If the first conductivity-type semiconductor layer 122 is ann-type semiconductor layer, the first conductivity-type dopant may be ann-type dopant including Si, Ge, Sn, Se, or Te, but is not limitedthereto. If the first conductivity-type semiconductor layer 122 is ap-type semiconductor layer, the first conductivity-type dopant may be ap-type dopant including Mg, Zn, Ca, Sr, or Ba, but is not limitedthereto.

The first conductivity-type semiconductor layer 122 may include asemiconductor material having a compositional formula ofAlxInyGa(1−x−y)N (0≦x≦1, 0≦y≦1, 0≦x+y≦1). The first conductivity-typesemiconductor layer 122 may be formed of at least one of GaN, InN, AlN,InGaN, AlGaN, InAlGaN, AlInN, AlGaAs, InGaAs, AlInGaAs, GaP, AlGaP,InGaP, AlInGaP, and InP.

The second conductivity-type semiconductor layer 126 may be formed of asemiconductor compound, for example, a group III-V or group II-VIcompound semiconductor. Further, the second conductivity-typesemiconductor layer 126 may be doped with a second conductivity-typedopant. The second conductivity-type semiconductor layer 126 may includea semiconductor material having a compositional formula ofInxAlyGa(1−x−y)N (0≦x≦1, 0≦y≦1, 0≦x+y≦1). The second conductivity-typesemiconductor layer 126 may be formed of at least one of GaN, InN, AlN,InGaN, AlGaN, InAlGaN, AlInN, AlGaAs, InGaAs, AlInGaAs, GaP, AlGaP,InGaP, AlInGaP, and InP. If the second conductivity-type semiconductorlayer 126 is a p-type semiconductor layer, the second conductivity-typedopant may be a p-type dopant including Mg, Zn, Ca, Sr, or Ba, but isnot limited thereto. If the second conductivity-type semiconductor layer126 is an n-type semiconductor layer, the second conductivity-typedopant may be an n-type dopant including Si, Ge, Sn, Se, or Te, but isnot limited thereto.

Hereinafter, the case in which the first conductivity-type semiconductorlayer 122 is an n-type semiconductor layer and the second conductivesemiconductor layer 126 is a p-type semiconductor layer will beexemplarily described.

A semiconductor layer having polarity opposite to the secondconductivity-type semiconductor layer 126, for example, an n-typesemiconductor layer (not shown) if the second conductivity-typesemiconductor layer 126 is a p-type semiconductor layer, may be formedon the second conductivity-type semiconductor layer 126. Thereby, thelight emitting structure may be formed in one structure of an n-pjunction structure, a p-n junction structure, an n-p-n junctionstructure, and a p-n-p junction structure.

The active layer 124 may be disposed between the first conductivity-typesemiconductor layer 122 and the second conductivity-type semiconductorlayer 126.

The active layer 124 emits light having energy determined by theintrinsic energy band of an active layer (emission layer) material dueto contact between electrons and holes. If the first conductivity-typesemiconductor layer 122 is an n-type semiconductor layer and the secondconductivity-type semiconductor layer 126 is a p-type semiconductorlayer, electrons may be injected into the active layer 124 from thefirst conductivity-type semiconductor layer 122 and holes may beinjected into the active layer 124 from the second conductivity-typesemiconductor layer 126.

The active layer 124 may be formed in at least one structure of a singlequantum well structure, a multi-quantum well structure, a quantum wirestructure, and a quantum dot structure. For example, the active layer124 may be formed in a multi-quantum well structure through injection ofTMGa, NH3, N2, or TMIn gas, but is not limited thereto.

If the active layer 124 is formed in a multi-quantum well structure,well/barrier layers of the active layer 124 may be formed in at leastone paired structure of InGaN/GaN, InGaN/InGaN, GaN/AlGaN, InAlGaN/GaN,GaAs(InGaAs)/AlGaAs, and GaP(InGaP)/AlGaP, but are not limited thereto.The well layer may be formed of a material having a bandgap less thanthe bandgap of the barrier layer.

A buffer layer 115 may be disposed between the light emitting structure120 and the substrate 110. The buffer layer 115 serves to relievelattice mismatch of materials and a difference of thermal expansioncoefficients between the light emitting structure 120 and the substrate110. The buffer layer 115 may be formed of a group III-V compoundsemiconductor, for example, at least one of GaN, InN, AlN, InGaN,InAlGaN, and AlInN.

An undoped semiconductor layer (not shown) may be disposed between thesubstrate 110 and the first conductivity-type semiconductor layer 122.The undoped semiconductor layer serves to enhance crystallinity of thefirst conductivity-type semiconductor layer 122, and may be the same asthe first conductivity-type semiconductor layer 122 except that theundoped semiconductor layer is not doped with an n-type dopant and thushas electrical conductivity lower than the first conductivity-typesemiconductor layer 122.

The light emitting structure 120 includes an etching area S formed bypartially etching the light emitting structure 120 to expose the firstconductivity-type semiconductor layer 122. The etching area S means anarea of the first conductivity-type semiconductor layer 122 which isexposed to the outside by partially etching the second conductivity-typesemiconductor layer 126, the active layer 124, and the firstconductivity-type semiconductor layer 122.

The second electrode 140 is disposed on the second conductivity-typesemiconductor layer 126 and is electrically connected to the secondconductivity-type semiconductor layer 126.

The first electrode 130 is disposed in the etching area S of the firstconductivity-type semiconductor layer 122 exposed to the outside byetching and is electrically connected to the first conductivity-typesemiconductor layer 122.

The first electrode 130 and the second electrode 140 may be formed in asingle layered structure or a multi-layered structure including at leastone of molybdenum (Mo), chrome (Cr), nickel (Ni), gold (Au), aluminum(Al), titanium (Ti), platinum (Pt), vanadium (V), tungsten (W), lead(Pd), copper (Cu), rhodium (Rh), and iridium (Ir).

Before formation of the second electrode 140, a conductive layer 150 maybe disposed on the second conductivity-type semiconductor layer 126.

According to embodiments, a part of the conductive layer 150 may beopened to expose the second conductivity-type semiconductor layer 126and thus, the second conductivity-type semiconductor layer 126 and thesecond electrode 140 may contact each other.

Otherwise, as exemplarily shown in FIG. 3, the second conductivity-typesemiconductor layer 126 and the second electrode 140 may be electricallyconnected to each other under the condition that the conductive layer150 is disposed therebetween.

The conductive layer 150 serves to enhance electrical characteristics ofthe second conductivity-type semiconductor layer 126 and electricalcontact between the second conductivity-type semiconductor layer 126 andthe second electrode 140, and may be formed in a layer or a plurality ofpatterns. The conductive layer 150 may be a transparent electrode layerhaving transmittance.

The conductive layer 150 may selectively use a light-transmittingconductive layer and a metal, and, for example, include at least one ofindium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide(IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide(IGZO), indium gallium tin oxide (IGTO), aluminum zinc oxide (AZO),antimony tin oxide (ATO), gallium zinc oxide (GZO), IZO nitride (IZON),Al—GaZnO (AGZO), In—GaZnO (IGZO), ZnO, IrOx, RuOx, NiO, RuOx/ITO,Ni/IrOx/Au, Ni/IrOx/Au/ITO, Ag, Ni, Cr, Ti, Al, Rh, Pd, Ir, Sn, In, Ru,Mg, Zn, Pt, Au, and Hf, but is not limited thereto.

The conductive interconnection layer 170 is disposed between twoneighboring light emitting cells 100. The conductive interconnectionlayer 170 electrically connects the two neighboring light emitting cells100. The conductive interconnection layer 170 connects the firstelectrode 130 of one of the two neighboring light emitting cells 100 andthe second electrode 140 of the other of the two neighboring lightemitting cells 100, as exemplarily shown in FIGS. 1A to 3, and thus, theplural light emitting cells 100 may be connected in series. FIG. 1B is acircuit diagram briefly illustrating the plural light emitting cells 100connected in series. Otherwise, although not shown in the drawings, theconductive interconnection layer 170 may connect the electrodes havingthe same polarity of the two neighboring light emitting cells 100, i.e.,the first electrodes 130 or the second electrodes 140, and thus, theplural light emitting cells 100 may be connected in parallel.

For example, with reference to FIG. 3, the conductive interconnectionlayer 170 electrically connects two neighboring light emitting cells 100a and 100 b. Specifically, the conductive interconnection layer 170extends from the second electrode 140 of one light emitting cell 100 aof the two neighboring light emitting cells 100 a and 100 b to the firstelectrode 130 of the other light emitting cell 100 b along the sidesurface of the light emitting cell 100 a and the side surface of thelight emitting cell 100 b and may thus connect the two neighboring lightemitting cells 100 a and 100 b in series.

With reference to FIG. 3, the two neighboring light emitting cells 100 aand 100 b are separated from each other. Further, an insulating layer160 is disposed on the side and upper surfaces of each of the lightemitting structures 120. The insulating layer 160 may be disposed in theremainder of the side and upper surfaces of the light emitting structure120 except for areas where the first electrode 130 and the secondelectrode 140 are disposed. The insulating layer 160 is disposed betweenthe light emitting cells 100 and the conductive interconnection layer170 in a region where the conductive interconnection layer 170 ispresent.

The insulating layer 160 serves to electrically isolate the neighboringlight emitting cells 100 from each other or to electrically isolate theconductive interconnection layer 170 and the light emitting cells 100from each other.

The insulating layer 160 may be formed of a non-conductive oxide ornitride, for example, silicon oxide (SiO2), silicon nitride, or aluminumoxide, but is not limited thereto.

With reference to FIGS. 1A to 3, the light emitting structure 120includes a first side surface 120 a adjacent to the second electrode 140and parallel with the second electrode 140, and a second side surface120 b opposite to the first side surface 120 a and contacting theetching area S. Being parallel with the second electrode 140 means beingparallel with the longitudinal direction of the second electrode 140.The longitudinal direction of the second electrode 140 means a directionin which the longest side of the second electrode 140 is arranged.

The second side surface 120 b contacts the etching area S in which thefirst electrode 130 is disposed, and is disposed at a designated angle θfrom the etching area S. The angle θ between the etching area S and thesecond side surface 120 b may be 90 degrees or more. The second sidesurface 120 b corresponds to one side surface of the light emittingstructure 120 exposed to the outside by etching, when the light emittingstructure 120 is partially etched to form the etching area S.

As seen from the top, the second electrodes 140 of the plural lightemitting cells 100 are disposed in a first direction parallel with thefirst side surface 120 a.

If a width between the first side surface 120 a and the second sidesurface 120 b is defined as W, as seen from the top, the secondelectrode 140 is disposed in an area D between a position separated fromthe first side surface 120 a by

$\frac{1}{5}W$and a position separated from the first side surface 120 a by

$\frac{1}{2}{W.}$

In order to enhance luminous intensity of the light emitting device 100Aand to lower operating voltage of the light emitting device 100A,uniform spreading of current injected from the first electrode 130 andthe second electrode 140 throughout the overall surface of the lightemitting structure 120 is important. If the second electrode 140 isdisposed in an area within the position separated from the first sidesurface 120 a by

${\frac{1}{5}W},$the separation distance between the first electrode 130 and the secondelectrode 140 is increased and thus, current spreading is noteffectively carried out, and if the second electrode 140 is disposed inan area exceeding the position separated from the first side surface 120a by

${\frac{1}{2}W},$the distance between the second electrode 140 and the first side surface120 a is increased and thus, current spreading is not effectivelycarried out.

FIG. 4 is a graph illustrating output power (Po.) and operating voltage(Vf) according to positions of the second electrode when the secondelectrode is disposed in accordance with the embodiment.

With reference to FIG. 4, it may be confirmed that, as the secondelectrode 140 moves from a position separated from the first sidesurface 120 a by a distance of

$\frac{1}{5}W$to a position separated from the first side surface 120 a by a distanceof

${\frac{1}{2}W},$output power (Po.) is increased and operating voltage (Vf) is decreased.Particularly, as the second electrode 140 moves from the positionseparated from the first side surface 120 a by a distance of

$\frac{1}{5}W$to a position separated from the first side surface 120 a by a distanceof

${\frac{2}{5}W},$enhancement effect of the output power (Po.) and the operating voltage(Vf) is great. Further, as the second electrode 140 moves from theposition separated from the first side surface 120 a by a distance of

$\frac{2}{5}W$to the position separated from the first side surface 120 a by adistance of

${\frac{1}{2}W},$enhancement effect of the output power (Po.) and the operating voltage(Vf) is converged.

Table 1 states detailed values at positions of the second electrode 140separated from the first side surface 120 a by distances of

${\frac{1}{5}W},{\frac{2}{5}W},{{and}\mspace{14mu}\frac{1}{2}{W.}}$

TABLE 1 Position of second electrode Po.[mV] Vf[V] $\frac{1}{5}W$ 20.363.07 $\frac{2}{5}W$ 20.97 3 $\frac{1}{2}W$ 21 2.99

That is, when the distance between the first electrode 130 and thesecond electrode 140 is optimized, current spreading is effectivelycarried out and thus, output power is increased and operating voltage(Vf) is decreased.

Referring to FIG. 2 again, at least one of the plural conductiveinterconnection layers 170 may be disposed in a second directiondiffering from the first direction. According to embodiments, the seconddirection may be vertical to the first direction.

As both ends of the conductive interconnection layer 170 respectivelyoverlap with the second electrode 140 of one light emitting cell 100 aof the neighboring light emitting cells 100 a and 100 b and the firstelectrode 130 of the other light emitting cell 100 b, the conductiveinterconnection layer 170 electrically connects the neighboring lightemitting cells 100 a and 100 b.

In order to minimize absorption of light generated in the active layer124, the width of a portion of the conductive interconnection layer 170disposed on the light emitting structure 120 may be less than the widthof a portion of the conductive interconnection layer 170 disposedbetween the neighboring light emitting cells 100 a and 100 b.

FIG. 5 is an enlarged view of the portion B of FIG. 1.

With reference to FIG. 5, at least one of the plural conductiveinterconnection layers 170 may be disposed in the first direction. Here,the first electrode 130 of one light emitting cell 100 d of twoneighboring light emitting cells 100 b and 100 d may be disposed at theedge area of the light emitting cell 100 d in order to minimize loss ofthe active layer 124, and the second electrode 140 of the other lightemitting cell 100 b may be disposed an area D between a positionseparated from the first side surface 120 a by a distance of

$\frac{1}{5}W$and a position separated from the first side surface 120 a by a distanceof

${\frac{1}{2}W},$so that the first electrode 130 and the second electrode 140 may not bedisposed on the same line, i.e., may be disposed on different lines.Therefore, the first electrode 130 of the light emitting cell 100 dcontacting the conductive interconnection layer 170 disposed in thefirst direction may include a bent part G.

With reference to FIG. 1, according to embodiments, a region at whichthe conductive interconnection layer 170 disposed in the first directionis disposed may be a region of the light emitting device 100A in whichthe arrangement direction of the light emitting cells 100 is changed.

With reference to FIG. 1, a light emitting cell 100Z1 present at one endof arrangement of the plural light emitting cells 100 may include anelectrode pad 140 p in the second electrode 140 so as to secure adimension for wire-bonding. In the same manner, a light emitting cell100Z2 present at another end of arrangement of the plural light emittingcells 100 may include an electrode pad 130 p in the first electrode 130so as to secure a dimension for wire-bonding.

FIG. 6A is a plan view of a light emitting device in accordance withanother embodiment, FIG. 6B is a circuit diagram of the light emittingdevice, and FIG. 7 is an enlarged view of the portion C of FIG. 6.Illustration of a cross-sectional view of the light emitting device inaccordance with this embodiment is omitted and FIG. 3 will be referredto. A detailed description of some parts in this embodiment which aresubstantially the same as those in the earlier embodiment will beomitted because it is considered to be unnecessary.

With reference to FIGS. 6A to 7, a light emitting device 100B inaccordance with this embodiment includes a substrate 110, a plurality oflight emitting cells 100 separated from each other and provided on thesubstrate 110, and a plurality of conductive interconnection layers 170electrically connecting two neighboring light emitting cells 100.

Each of the plurality of light emitting cells 100 includes a lightemitting structure 120 including a first conductivity-type semiconductorlayer 122, an active layer 124 and a second conductivity-typesemiconductor layer 126, a first electrode 130 disposed on the firstconductivity-type semiconductor layer 122, and a second electrode 140disposed on the second conductivity-type semiconductor layer 126.

The light emitting structure 120 includes an etching area S formed bypartially etching the light emitting structure 120 so as to expose thefirst conductivity-type semiconductor layer 122. The etching area Smeans an area of the first conductivity-type semiconductor layer 122exposed to the outside by partially etching the second conductivity-typesemiconductor layer 126, the active layer 124, and the firstconductivity-type semiconductor layer 122.

The conductive interconnection layer 170 is disposed between twoneighboring light emitting cells 100. The conductive interconnectionlayer 170 electrically connects the two neighboring light emitting cells100.

The second electrode 140 includes a first part 140 a and a second part140 b connected to the first part 140 a and disposed in a differentdirection from the first part 140 a.

The light emitting structure 120 includes a first side surface 120 aadjacent to the first part 140 a of the second electrode 140 andparallel with the first part 140 a, and a second side surface 120 bopposite to the first side surface 120 a and contacting the etching areaS. Being parallel with the first part 140 a of the second electrode 140means being parallel with the longitudinal direction of the first part140 a. The longitudinal direction of the first part 140 a means adirection in which the longest side of the first part 140 a is arranged.

The first part 140 a of the second electrode 140 is disposed in a firstdirection parallel with the first side surface 120 a, and the secondpart 140 b of the second electrode 140 is disposed in a second directiondiffering from the first direction. According to embodiments, the seconddirection may be vertical to the first direction.

If a width between the first side surface 120 a and the second sidesurface 120 b is defined as W, as seen from the top, the first part 140a of the second electrode 140 is disposed within an area D between aposition separated from the first side surface 120 a by a distance of

$\frac{1}{5}W$and a position separated from the first side surface 120 a by a distanceof

$\frac{1}{2}{W.}$Here, the second part 140 b of the second electrode 140 may be disposedwithin the area D, or at least a portion of the second part 140 b maydeviate from the area D.

In order to enhance luminous intensity of the light emitting device 100Band to lower operating voltage of the light emitting device 100B,uniform spreading of current injected from the first electrode 130 andthe second electrode 140 throughout the overall surface of the lightemitting structure 120 is important. If the first part 140 a of thesecond electrode 140 is disposed in an area within the positionseparated from the first side surface 120 a by a distance of

${\frac{1}{5}W},$the separation distance between the first electrode 130 and the secondelectrode 140 is increased and thus, current spreading is noteffectively carried out, and if the first part 140 a of the secondelectrode 140 is disposed in an area exceeding the position separatedfrom the first side surface 120 a by a distance of

${\frac{1}{2}W},$the distance between the second electrode 140 and the first side surface120 a is increased and thus, current spreading is not effectivelycarried out.

The second electrode 140 including the first part 140 a and the secondpart 140 b may more effectively achieve current spreading than thesecond electrode 140 including only the first part 140 a.

The first part 140 a of the second electrode 140 may be elongated, ascompared to the second part 140 b. That is, the length of the first part140 a corresponding to the long direction of the light emittingstructure 120 may be greater than the length of the second part 140 bcorresponding to the short direction of the light emitting structure120.

At least one of the plural conductive interconnection layers 170 isdisposed in a second direction differing from the first direction.

As both ends of the conductive interconnection layer 170 respectivelyoverlap with the first electrode 130 of one light emitting cell 100 a ofthe neighboring light emitting cells 100 a and 100 b and the secondelectrode 140 of the other light emitting cell 100 b, the conductiveinterconnection layer 170 electrically connects the neighboring lightemitting cells 100 a and 100 b. Otherwise, as both ends of theconductive interconnection layer 170 respectively overlap with the firstelectrode 130 of one light emitting cell 100 b of the neighboring lightemitting cells 100 a and 100 b and the second electrode 140 of the otherlight emitting cell 100 a, the conductive interconnection layer 170electrically connects the neighboring light emitting cells 100 a and 100b.

Further, at least one of the plural conductive interconnection layers170 may be disposed in the first direction. Here, the first electrode130 of one light emitting cell 100 d of two neighboring light emittingcells 100 b and 100 d may be disposed at the edge area of the lightemitting cell 100 d in order to minimize loss of the active layer 124,and the first part 140 a of the second electrode 140 of the other lightemitting cell 100 b may be disposed an area D between a positionseparated from the first side surface 120 a by a distance of

$\frac{1}{5}W$and a position separated from the first side surface 120 a by a distanceof

${\frac{1}{2}W},$so that the first electrode 130 of the light emitting cell 100 d and thefirst part 140 a of the second electrode 140 of the light emitting cell100 b may not be disposed on the same line. Therefore, the firstelectrode 130 of the light emitting cell 100 d contacting the conductiveinterconnection layer 170 disposed in the first direction may include abent part G.

If the conductive interconnection layer 170 is disposed in the firstdirection, one end of the conductive interconnection layer 170 mayoverlap with the second part 140 b of the second electrode 140.

According to embodiments, a region at which the conductiveinterconnection layer 170 disposed in the first direction is disposedmay be a region of the light emitting device 100B in which thearrangement direction of the light emitting cells 100 is changed.

FIG. 8 is a top view of a portion of a light emitting device inaccordance with another embodiment. A detailed description of some partsin this embodiment which are substantially the same as those in theearlier embodiments will be omitted because it is considered to beunnecessary.

A plurality of conductive interconnection layers 170 may be providedbetween two neighboring light emitting cells. For example, withreference to FIG. 8, two conductive interconnection layers 170 areprovided between two neighboring light emitting cells 100 b and 100 d,and two conductive interconnection layers 170 are provided between twoneighboring light emitting cells 100 a and 100 b.

The number of conductive interconnection layers 170 provided between twoneighboring light emitting cells may vary according to embodiments, andthe plural conductive interconnection layers 170 may be separated fromone another.

FIG. 9 is a view illustrating a light emitting device package having alight emitting device in accordance with one embodiment.

A light emitting device package 300 in accordance with this embodimentincludes a body 310, a first lead frame 321 and a second lead frame 322disposed on the body 310, a light emitting device 100 in accordance withone of the above-described embodiments, disposed on the body 310 andelectrically connected to the first lead frame 321 and the second leadframe 322, and a molding part 340 formed in a cavity. The cavity may beformed in the body 310. The light emitting device 100 is one chipincluding a plurality of light emitting cells connected in series or inparallel, as described above.

The body 310 may be formed of silicon, a synthetic resin, or metal. Ifthe body 310 is formed of a conductive material, such as metal, thesurface of the body 310 may be coated with an insulating layer (notshown) so as to prevent an electrical short circuit between the firstand second lead frames 321 and 322.

The first lead frame 321 and the second lead frame 322 are electricallyisolated and supply current to the light emitting device 100. Further,the first lead frame 321 and the second lead frame 322 may reflect lightemitted from the light emitting device 100 to increase luminanceefficiency, and dissipate heat generated by the light emitting device100 to the outside.

The light emitting device 100 may be disposed on the body 310, or bedisposed on the first lead frame 321 or the second lead frame 322. Inthis embodiment, the first lead frame 321 and the light emitting device100 are directly electrically connected, and the second lead frame 322and the light emitting device 100 are electrically connected through awire 330. The light emitting device 100 may be connected to the leadframes 321 and 322 by flip chip-bonding or die-bonding in addition towire-bonding.

The molding part 340 may surround and protect the light emitting device100. Further, the molding part 340 may include a phosphor 350, thuschanging the wavelength of light emitted from the light emitting device100.

The phosphor 350 may be a garnet phosphor, a silicate phosphor, anitride phosphor, or oxynitride phosphor.

For example, the garnet phosphor may be YAG(Y3Al5O12:Ce3+) orTAG(Tb3Al5O12:Ce3+), the silicate phosphor may be (Sr, Ba, Mg,Ca)2SiO4:Eu2+, the nitride phosphor may be CaAlSiN3:Eu2+ including SiN,and the oxynitride phosphor may be Si6−xAlxOyN8−x:Eu2+(0<x<6) includingSiON.

Light of a first wavelength emitted from the light emitting device 100may be excited by the phosphor 350 and be converted into light of asecond wavelength, and as the light of the second wavelength passesthrough a lens (not shown), a light path may be changed.

Plural light emitting device packages in accordance with this embodimentmay be arranged on a substrate, and optical members, such as a lightguide panel, a prism sheet, a diffusion sheet, etc., may be disposed ona light path of the light emitting device packages. The light emittingdevice packages, the substrate, and the optical members may function asa light unit. Another embodiment may implement a display device, anindicator device, or a lighting system including the semiconductor lightemitting devices or the light emitting device packages in accordancewith the above-described embodiments, and the lighting system mayinclude, for example, a lamp or a streetlamp.

Hereinafter, as examples of a lighting system including theabove-described light emitting devices or light emitting devicepackages, a backlight unit and a lighting apparatus will be described.

FIG. 10 is a view illustrating a display device having light emittingdevice packages in accordance with one embodiment.

With reference to FIG. 10, a display device 800 in accordance with thisembodiment includes a light emitting module, a reflective plate 820 on abottom cover 810, a light guide panel 840 disposed in front of thereflective plate 820 and guiding light emitted from the light emittingmodule in the forward direction of the display device 800, a first prismsheet 850 and a second prism sheet 860 disposed in front of the lightguide panel 840, a panel 870 disposed in front of the second prism sheet860, and a color filter 880 disposed in front of the panel 870.

The light emitting module includes light emitting device packages 835disposed on a circuit board 830. Here, a PCB may be used as the circuitboard 830, and each light emitting device package 835 may be the lightemitting device package described above with reference to FIG. 9.

The bottom cover 819 may accommodate components within the displaydevice 800. The reflective plate 820 may be separately provided, asshown in FIG. 10, or be provided by coating the rear surface of thelight guide panel 840 or the front surface of the bottom cover 810 witha material having high reflectivity.

Here, the reflective plate 820 may be formed of a material which hashigh reflectivity and is usable in an ultra-thin type, and be formed ofpolyethyleneterephtalate (PET).

The light guide panel 840 scatters light emitted from the light emittingmodule so that the light may be uniformly distributed throughout theentire area of a screen of a liquid crystal display device. Therefore,the light guide panel 840 may be formed of a material having a highrefractive index and high transmissivity, for example,polymethylmethacrylate (PMMA), polycarbonate (PC), or polyethylene (PE).Further, an air guide type in which the light guide panel 840 is omittedand light is transmitted in a space above the reflective sheet 820 maybe employed.

The first prism sheet 850 is formed by applying a light-transmitting andelastic polymer to one surface of a support film. The polymer may have aprism layer in which plural 3D structures are repeated. Here, the pluralstructures may be provided in a stripe pattern in which projections anddepressions are repeated, as shown in FIG. 10.

The direction of projections and depressions formed on one surface of asupport film of the second prism sheet 860 may be vertical to thedirection of the projections and the depressions formed on one surfaceof the support film of the first prism sheet 850. This serves touniformly disperse light transmitted from the light emitting module andthe reflective sheet 820 in all directions of the panel 870.

In this embodiment, the first prism sheet 850 and the second prism sheet860 are used as the optical sheets. The optical sheets may include othercombinations, for example, a micro-lens array, a combination of adiffusion sheet and a micro-lens array, or a combination of one prismsheet and a micro-lens array.

As the panel 870, a liquid crystal display panel may be provided.Further, in addition to the liquid crystal display panel, other kinds ofdisplay device requiring light sources may be provided.

The panel 870 is configured such that liquid crystals are providedbetween two glass bodies and polarizing plates are respectively mountedon the glass bodies so as to utilize polarization of light. Here, liquidcrystals have intermediate properties between a liquid and a solid inwhich organic molecules having fluidity like a liquid, i.e., liquidcrystals, are regularly arranged, and display an image using change ofmolecular arrangement by an external electric field.

The liquid crystal display panel used in the display device is an activematrix type, and uses transistors as switches to adjust voltage appliedto respective pixels.

The color filter 880 is provided on the front surface of the panel 870,and transmits only red, green and blue light among light projected bythe panel 870 per pixel, thus displaying an image.

FIG. 11 is a view illustrating a lighting apparatus having lightemitting devices or light emitting device packages in accordance withone embodiment.

A lighting apparatus in accordance with this embodiment may include acover 1100, a light source module 1200, a heat sink 1400, a power supplyunit 1600, an inner case 1700, and a socket 1800. The lighting apparatusin accordance with this embodiment may further include at least one of amember 1300 and a holder 1500, and the light source module 1200 mayinclude light emitting device packages in accordance with theabove-described embodiment.

The cover 1100 may have a bulb or hemispheric shape which is hollow andis provided with one opened end. The cover 1100 may be opticallycombined with the light source module 1200. For example, the cover 1100may diffuse, scatter, or excite light supplied from the light sourcemodule 1200. The cover 1100 may be a kind of optical member. The cover1100 may be combined with the heat sink 1400. The cover 1100 may have aconnection part to be combined with the heat sink 1400.

The inner surface of the cover 1100 may be coated with a milk-whitepaint. The milk-white paint may include a light diffuser diffusinglight. Surface roughness of the inner surface of the cover 1100 may begreater than surface roughness of the outer surface of the cover 1100.This serves to sufficiently scatter and diffuse light emitted from thelight source module 1200 and to discharge the light to the outside.

The cover 1100 may be formed of glass, plastic, polypropylene (PP),polyethylene (PE), polycarbonate (PC), etc. Here, polycarbonate (PC) hasexcellent light resistance, heat resistance, and strength. The cover1100 may be transparent so that the light source module 1200 is visiblefrom the outside, or be opaque. The cover 1100 may be formed by blowmolding.

The light source module 1200 may be disposed on one surface of the heatsink 1400. Therefore, heat from the light source module 1200 isconducted to the heat sink 1400. The light source module 1200 mayinclude light emitting device packages 1210, connection plates 1230, anda connector 1250.

The member 1300 may be disposed on the upper surface of the heat sink1400, and include guide holes 1310 into which the plural light emittingdevice packages 1210 and the connector 1250 are inserted. The guideholes 1310 correspond to substrates of the light emitting devicepackages 1210 and the connector 1250.

A light reflecting material may be applied to or coated on the surfaceof the member 1300. For example, a white paint may be applied to orcoated on the surface of the member 1300. The member 1300 reflectslight, reflected by the inner surface of the cover 1100 and returning inthe direction toward the light source module 1200, to the cover 1100.Therefore, the member 1300 may enhance luminance efficiency of thelighting apparatus in accordance with this embodiment.

The member 1300 may be formed of, for example, an insulating material.The connection plates 1230 of the light source module 1200 may includean electrically conductive material. Therefore, the heat sink 1400 andthe connection plates 1230 may electrically contact each other. Themember 1300 formed of an insulating material may prevent electricalshort circuit between the connection plates 1230 and the heat sink 1400.The heat sink 1400 receives heat from the light source module 1200 andthe power supply unit 1600, and dissipates the heat.

The holder 1500 closes an accommodation hole 1719 of an insulating part1710 of the inner case 1700. Therefore, the power supply unit 1600accommodated in the insulating part 1710 of the inner case 1700 ishermetically sealed. The holder 1600 has a guide protrusion 1510. Theguide protrusion 1510 is provided with a hole through which protrusions1610 of the power supply unit 1600 pass.

The power supply unit 1600 processes or converts an electrical signalprovided from the outside, and then supplies the processed or convertedelectrical signal to the light source module 1200. The power supply unit1600 is accommodated in the accommodation hole 1719 of the inner case1700, and is hermetically sealed within the inner case 1700 by theholder 1500. The power supply unit 1600 may include the protrusions1610, a guide part 1630, a base 1650, and an extension 1670.

The guide part 1630 protrudes from one side of the base 1650 to theoutside. The guide part 1630 may be inserted into the holder 1500.Plural components may be disposed on one surface of the base 1650. Forexample, the plural components may include an AC/DC converter convertingAC power supplied from an external power source into DC power, a drivechip controlling driving of the light source module 1200, and anelectrostatic discharge (ESD) protection element to protect the lightsource module 1200, but are not limited thereto.

The extension 1670 protrudes from the other side of the base 1650 to theoutside. The extension 1670 is inserted into a connection part 1750 ofthe inner case 1700 and receives an electrical signal provided from theoutside. For example, the extension 1670 may have a width equal to orsmaller than the width of the connection part 1750 of the inner case1700. One end of each of a positive (+) electric wire and a negative (−)electric wire may be electrically connected to the extension 1670, andthe other end of each of the positive (+) electric wire and the negative(−) electric wire may be electrically connected to the socket 1800.

The inner case 1700 may include a molding part together with the powersupply unit 160 therein. The molding part is formed by hardening amolding liquid, and serves to fix the power supply unit 160 within theinner case 1700.

As is apparent from the above description, a light emitting device inaccordance with one embodiment may enhance current spreading between afirst electrode and a second electrode, thus enhancing luminousintensity and lowering operating voltage.

Embodiments provide a light emitting device in which current spreadingis enhanced.

In one embodiment, a light emitting device includes a substrate, aplurality of light emitting cells separated from each other and disposedon the substrate, and a plurality of conductive interconnection layerselectrically connecting two neighboring light emitting cells, whereineach of the plurality of light emitting cells includes a light emittingstructure including a first conductivity-type semiconductor layer, anactive layer and a second conductivity-type semiconductor layer, a firstelectrode disposed on the first conductivity-type semiconductor layer, asecond electrode disposed on the second conductivity-type semiconductorlayer, and an etching area, in which the first conductivity-typesemiconductor layer is exposed, formed by partially etching the lightemitting structure, wherein the light emitting structure furtherincludes a first side surface adjacent to the second electrode andparallel with the second electrode and a second side surface opposite tothe first side surface and contacting the etching area, and if a widthbetween the first side surface and the second side surface is defined asW, as seen from the top, the second electrode is disposed in an areabetween a position separated from the first side surface of the lightemitting structure by

$\frac{1}{5}W$and a position separated from the first side surface of the lightemitting structure by

$\frac{1}{2}{W.}$

The second electrode may be disposed in a first direction parallel withthe first side surface, and at least one of the plurality of conductiveinterconnection layers may be disposed in the first direction.

The second electrode may be disposed in a first direction parallel withthe first side surface, and at least one of the plurality of conductiveinterconnection layers may be disposed in a second direction differingfrom the first direction.

The second electrode may include a first part disposed in a firstdirection parallel with the first side surface and a second partdisposed in a second direction differing from the first direction.

One end of at least one of the plurality of conductive interconnectionlayers may overlap with the second part.

One of the plurality of conductive interconnection layers may connectthe first electrode of one of the two neighboring light emitting cellsand the second electrode of the other of the two neighboring lightemitting cells.

Plurality of the conductive interconnection layers may be providedbetween the two neighboring light emitting cells.

The light emitting device may further include an insulating layerdisposed on the side surfaces of each of the plurality of light emittingcells, and the insulating layer electrically may isolate the twoneighboring light emitting cells and/or the plurality of conductiveinterconnection layers and the plurality of light emitting cells.

At least a portion of the second part may deviate from the area betweenthe position separated from the first side surface of the light emittingstructure by

$\frac{1}{5}W$and the position separated from the first side surface of the lightemitting structure by

$\frac{1}{2}{W.}$

Plurality of the conductive interconnection layers may connect pluralityof the light emitting cells in series or in parallel.

The second side surface may be disposed at a predetermined angle fromthe etching area.

The width of a portion of the conductive interconnection layer disposedon the light emitting cell may be less than the width of a portion ofthe conductive interconnection layer disposed between the twoneighboring light emitting cells.

The first electrode of one light emitting cell may be disposed at theedge of the light emitting cell.

The second electrode of another light emitting cell adjacent to thelight emitting cell may be disposed on a line differing from the line onwhich the first electrode of the light emitting cell is disposed.

The first electrode of the light emitting cell contacting the at leastone conductive interconnection layer disposed in the first direction mayinclude a bent part.

The arrangement direction of the neighboring light emitting cells in aregion at which the plurality of conductive interconnection layers maybe differ from the arrangement direction of the neighboring lightemitting cells in other regions.

The length of the first part of the second electrode may be greater thanthe length of the second part of the second electrode.

Plurality of conductive interconnection layers may be disposed in afirst direction and a second direction different to the first direction.

In another embodiment, a light emitting device includes a substrate, aplurality of light emitting cells separated from each other and disposedon the substrate, and a plurality of conductive interconnection layerselectrically connecting two neighboring light emitting cells, whereineach of the plurality of light emitting cells includes a light emittingstructure including a first conductivity-type semiconductor layer, anactive layer and a second conductivity-type semiconductor layer, a firstelectrode disposed on the first conductivity-type semiconductor layer, asecond electrode disposed on the second conductivity-type semiconductorlayer, and an etching area, in which the first conductivity-typesemiconductor layer is exposed, formed by partially etching the lightemitting structure, wherein the light emitting structure furtherincludes a first side surface adjacent to the second electrode andparallel with the second electrode and a second side surface opposite tothe first side surface and contacting the etching area, and if a widthbetween the first side surface and the second side surface is defined asW, as seen from the top, the second electrode includes a first partdisposed in a first direction parallel with the first side surface and asecond part disposed in a second direction differing from the firstdirection, and at least a portion of the second part deviates from anarea between a position separated from the first side surface of thelight emitting structure by

$\frac{1}{5}W$and a position separated from the first side surface of the lightemitting structure by

$\frac{1}{2}{W.}$

In yet another embodiment, a light emitting device includes a substrate,a plurality of light emitting cells separated from each other anddisposed on the substrate, and a plurality of conductive interconnectionlayers electrically connecting two neighboring light emitting cells,wherein each of the plurality of light emitting cells includes a lightemitting structure including a first conductivity-type semiconductorlayer, an active layer and a second conductivity-type semiconductorlayer, a first electrode disposed on the first conductivity-typesemiconductor layer, a second electrode disposed on the secondconductivity-type semiconductor layer, and an etching area, in which thefirst conductivity-type semiconductor layer is exposed, formed bypartially etching the light emitting structure, wherein the lightemitting structure further includes a first side surface adjacent to thesecond electrode and parallel with the second electrode and a secondside surface opposite to the first side surface and contacting theetching area, and if a width between the first side surface and thesecond side surface is defined as W, as seen from the top, the firstelectrode of one light emitting cell is disposed at the edge of thelight emitting cell and the second electrode of another light emittingcell adjacent to the light emitting cell is disposed on a line differingfrom the line on which the first electrode of the light emitting cell isdisposed.

Any reference in this specification to “one embodiment,” “anembodiment,” “example embodiment,” etc., means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment of the invention. Theappearances of such phrases in various places in the specification arenot necessarily all referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with any embodiment, it is submitted that it is within thepurview of one skilled in the art to effect such feature, structure, orcharacteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

What is claimed is:
 1. A light emitting device comprising: a substrate; a plurality of light emitting cells separated from each other and provided on the substrate, the plurality of light emitting cells including a first light emitting cell and a second light emitting cell, said second light emitting cell neighboring the first light emitting cell; a plurality of conductive interconnection layers, wherein a first one of the plurality of conductive interconnection layers electrically contacts the two neighboring light emitting cells, wherein each of the plurality of light emitting cells includes a light emitting structure including a first conductivity-type semiconductor layer, an active layer and a second conductivity-type semiconductor layer, a first electrode on the first conductivity-type semiconductor layer, a second electrode on the second conductivity-type semiconductor layer, and an etching area, in which the first conductivity-type semiconductor layer is exposed, formed by partially etching the light emitting structure, and an insulating layer along a first side surface of the light emitting structure of the first light emitting cell and along a second side surface of the light emitting structure of the second light emitting cell, wherein the second electrode includes a first part disposed in a first direction parallel with the first side surface and a second part disposed in a second direction differing from the first direction, wherein a length of the first part of the second electrode is greater than a length of the second part of the second electrode.
 2. The light emitting device according to claim 1, wherein the first one of the plurality of connective interconnect layers extends from the second electrode and along the first side surface of the light emitting structure of the first light emitting cell while on the insulating layer, and the first one of the plurality of conductive interconnect layers extends adjacent to the substrate and then along the second side surface of the light emitting structure of the second light emitting cell while on the insulating layer.
 3. The light emitting device according to claim 1, wherein the light emitting structure of the first light emitting cell includes the first side surface adjacent to the second electrode and parallel with the second electrode, and the light emitting structure of the second light emitting cell includes the second side surface opposite to the first side surface of the first light emitting cell and contacting the etching area.
 4. The light emitting device according to claim 1, wherein when a width between the first side surface and the second side surface is defined as W from a top view, the second electrode is provided in an area between a position separated from the first side surface of the light emitting structure by ⅕ W and a position separated from the first side surface of the light emitting structure by ½ W.
 5. The light emitting device according to claim 1, wherein the first part of the second electrode is disposed in the first direction parallel with the first side surface, and the first one of the plurality of conductive interconnection layers is provided in the first direction.
 6. The light emitting device according to claim 1, wherein the first part of the second electrode is provided in the first direction parallel with the first side surface, and at least one of the plurality of conductive interconnection layers is disposed in a second direction differing from the first direction.
 7. The light emitting device according to claim 1, wherein one end of the first one of the plurality of conductive interconnection layers overlaps with the second part of the second electrode.
 8. The light emitting device according to claim 1, wherein the first one of the plurality of conductive interconnection layers connects the first electrode of one of the two neighboring light emitting cells and the second electrode of the other one of the two neighboring light emitting cells.
 9. The light emitting device according to claim 1, wherein the insulating layer electrically isolates the two neighboring light emitting cells.
 10. The light emitting device according to claim 1, wherein at least a portion of the second part of the second electrode deviates from the area between the position separated from the first side surface of the light emitting structure by ⅕ W and the position separated from the first side surface of the light emitting structure by ½ W.
 11. The light emitting device according to claim 1, wherein the second side surface is disposed at a predetermined angle from the etching area.
 12. The light emitting device according to claim 1, wherein the width of a portion of the conductive interconnection layer on the light emitting cell is less than the width of a portion of the conductive interconnection layer disposed between the two neighboring light emitting cells.
 13. The light emitting device according to claim 1, wherein the first electrode of the second light emitting cell is provided at an edge of the second light emitting cell.
 14. The light emitting device according to claim 13, wherein the second electrode of the first light emitting cell adjacent to the second light emitting cell is provided on a line differing from the line on which the first electrode of the second light emitting cell is disposed.
 15. The light emitting device according to claim 5, wherein the first electrode of the second light emitting cell contacting the first one of the conductive interconnection layers disposed in the first direction includes a bent part.
 16. The light emitting device according to claim 1, wherein the plurality of conductive interconnection layers are provided in a first direction and a second direction different to the first direction.
 17. A light emitting device comprising: a substrate; a plurality of light emitting cells separated from each other and provided on the substrate, the plurality of light emitting cells including a first light emitting cell and a second light emitting cell, said second light emitting cell neighboring the first light emitting cell; a plurality of conductive interconnection layers, wherein a first one of the plurality of conductive interconnection layers electrically contacts the two neighboring light emitting cells, wherein each of the plurality of light emitting cells includes a light emitting structure including a first conductivity-type semiconductor layer, an active layer and a second conductivity-type semiconductor layer, a first electrode on the first conductivity-type semiconductor layer, a second electrode on the second conductivity-type semiconductor layer, and an etching area, in which the first conductivity-type semiconductor layer is exposed, formed by partially etching the light emitting structure, and an insulating layer along a first side surface of the light emitting structure of the first light emitting cell and along a second side surface of the light emitting structure of the second light emitting cell, wherein the second electrode includes a first part in a first direction parallel with the first side surface and a second part in a second direction differing from the first direction, and wherein a length of the first part of the second electrode is greater than a length of the second part of the second electrode, and wherein the light emitting structure of the first light emitting cell includes the first side surface adjacent to the second electrode and parallel with the second electrode, and the light emitting structure of the second light emitting cell includes the second side surface opposite to the first side surface and contacting the etching area, and when a width between the first side surface and the second side surface is defined as W from a top view.
 18. A light emitting device comprising: a substrate; a plurality of light emitting cells disposed on the substrate, the plurality of light emitting cells including a first light emitting cell and a second light emitting cell; a plurality of conductive interconnection layers, wherein a first one of the plurality of conductive interconnection layers electrically contacts two neighboring light emitting cells, wherein each of the plurality of light emitting cells includes a light emitting structure including a first conductivity-type semiconductor layer, an active layer and a second conductivity-type semiconductor layer, a first electrode on the first conductivity-type semiconductor layer, and a second electrode on the second conductivity-type semiconductor layer, and an insulating layer along a first side surface of the light emitting structure of the first light emitting cell and along a second side surface of the light emitting structure of the second light emitting cell, wherein when a width between the first side surface and the second side surface is defined as W from a top view, the first electrode of the second light emitting cell is provided at an edge of the second light emitting cell and the second electrode of the first light emitting cell adjacent to the second light emitting cell is provided on a line differing from a line on which the first electrode of the second light emitting cell is provided, wherein the second electrode includes a first part disposed in a first direction parallel with the first side surface and a second part disposed in a second direction differing from the first direction, and wherein a length of the first part of the second electrode is greater than a length of the second part of the second electrode.
 19. The light emitting device according to claim 18, wherein the light emitting structure of the first light emitting cell includes the first side surface adjacent to the second electrode and parallel with the second electrode, and the light emitting structure of the second light emitting cell includes the second side surface opposite to the first side surface.
 20. The light emitting device according to claim 1, wherein the second direction is parallel with the second surface. 